This invention relates to apparatus for determining the alignment of leads on a body and, more particularly, to electro-optical apparatus for determining the spacing between the leads on the body.
Quality control of products is of prime importance to a manufacturer, as well as an end user of the products. Quality control procedures are implemented at intermediate stages in the manufacture or assembly of the products, and final quality control procedures are employed on the finished products. The variety of quality control techniques are as varied as the different products being produced.
One type of manufactured product may be generally described as a body having at least one lead extending from the body. One particular example of such a product, made by semiconductor companies, is known as an integrated circuit package. Typically each side of the package has a plurality of leads extending from the package body. The leads on each side of the finished package must be substantially in-line, i.e., aligned with one another. Otherwise, a defect such as misalignment of the leads can cause premature electrical or mechanical failure during the end use of the package.
Though stringent quality control techniques may be employed during assembly of the package, a significant number of finished packages have one or more bent leads which are not in-line. For example, one or more leads can be bent towards one another along a line parallel to a longitudinal axis of the package, or can be bent away from one another along a line perpendicular to the parallel line, or can have a combined bending having a component along the parallel line and a component along the perpendicular line. Consequently, all finished packages should be tested and those packages having bent leads should be rejected.
Furthermore, the bodies of many types of packages may include a base and a cover for the base, with the leads being supported between the cover and the base. Quality control is also concerned with producing finished packages having the cover substantially, if not precisely, aligned over the base, edge-for-edge. However, in a number of finished packages, the edges of the cover are significantly offset from the edges of the base, which also is disadvantageous. Therefore, packages having this offset should be rejected.